JP3798270B2 - Method of charging the material to be melted into the melting furnace - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and an apparatus for charging a material to be melted into a melting furnace used when melting the material mainly composed of incinerated ash.
[0002]
[Prior art]
General waste such as municipal waste and industrial waste have been disposed of by landfill, but are now generally incinerated due to problems such as depletion of landfills and environmental destruction. However, even with the incineration treatment, since the incineration ash that is the treatment product contains harmful substances such as heavy metals and dioxins, there is a problem in the landfill treatment as it is.
Therefore, in recent years, incineration ash is put into a melting furnace and heated at a high temperature until it reaches a molten state, thereby detoxifying harmful substances and reducing the volume of processed products.
[0003]
By the way, as a conventional charging device for charging incineration ash into this type of melting furnace, for example, an extrusion supply device found in Japanese Patent No. 3065212 is known. In this extrusion supply device, a cylinder communicating with the melting furnace is formed at the bottom of a hopper attached to the melting furnace, a plurality of pushers are provided in the cylinder, and the reciprocating operation of the pusher is performed in a predetermined time cycle. In this way, the material to be melted in the cylinder is sequentially put into the furnace.
[0004]
[Problems to be solved by the invention]
However, in the above-described conventional method of charging the melt into the melting furnace, the pusher is driven at regular intervals, and the melt to be melted is charged into the furnace. If the properties such as the moisture content and the degree of flammability in the product and the input amount change, the furnace temperature will not be constant, and as a result, the incineration ash may be discharged without being completely melted. There was a point.
[0005]
On the other hand, a thermite type melting furnace is conventionally known as this type of melting furnace. This melting furnace uses the heat of combustion of fossil fuels (kerosene, light oil, etc.) by a burner installed in the furnace and the thermite reaction by the thermite agent mixed in the incineration ash to efficiently heat the incineration ash. To melt. Here, the thermite reaction is a mixture of aluminum and iron oxide powder and heated to a certain high temperature (about 1100 ° C.)
Fe ₂ O ₃ + 2Al = 2Fe + Al ₂ O ₃ +829 kJ
2Fe + 3 / 2O ₂ = Fe ₂ O ₃ +823 kJ
As shown by the following, thermite reaction is caused by reduction of iron oxide and oxidation of iron, and 1300 ° C. to 1500 ° C. required for melting the incinerated ash using a large amount of heat (829 kJ and 823 kJ) generated at this time A high temperature atmosphere of ℃ is obtained.
[0006]
For this reason, when the incinerated ash and the thermite agent are charged into the thermite melting furnace, if the conventional method of charging the melt into the melting furnace is used, the thermite reaction itself does not occur due to fluctuations in the furnace temperature. Since the problem that it becomes stable and thus it becomes difficult to smoothly melt the incinerated ash, it is desired to develop a method for charging a melt and a device for the melt that enable stable melting. .
[0007]
The present invention has been made in view of the above circumstances, and even when the properties of the material to be melted and the input amount have changed, the temperature atmosphere in the furnace can always be maintained in an optimum state for the melting treatment, Accordingly, it is an object of the present invention to provide a method and an apparatus for charging a material to be melted into a melting furnace that can continuously and smoothly carry out the melting treatment of incineration ash.
[0008]
[Means for Solving the Problems]
The method for charging a material to be melted into the melting furnace according to the first aspect of the present invention is mainly composed of incineration ash, and a thermit melting agent for causing a thermite reaction in a predetermined ratio with respect to the incineration ash. including the melt, a method of introducing the thermite type melting furnace having a heating means after the input means, as the furnace temperature to detect the temperature in the melting region of the object to be melt, the temperature is 1200 ° C. ~ When the set value selected from the range of 1400 ° C. is reached, the charging means is driven to input the material to be melted into the melting furnace. The set value is preferably a value selected from a range of 1250 ° C. to 1350 ° C. (that is, a range of 1300 ° C. ± 50 ° C.).
[0012]
According to the first aspect of the present invention, when the material to be melted is charged into the melting furnace by the charging means, the furnace temperature is once decreased, and then the furnace temperature is increased by heating in the furnace. A melting process is performed on the material to be melted. When the furnace temperature reaches a predetermined temperature, the melting means is always melted by repeating the operation of driving the charging means and charging the melt again into the melting furnace. Therefore, it is possible to continuously and smoothly carry out the melting process of the material to be melted mainly composed of incinerated ash.
[0013]
Therefore, after the furnace temperature is reliably raised to a temperature at which the thermite reaction occurs or higher and a desired melting process is performed, a new material to be melted can be charged. At this time, the position where the temperature in the furnace is detected is the melting region of the material to be melted, and the set temperature is in the range of 1200 ° C to 1400 ° C, preferably in the range of 1250 ° C to 1350 ° C. Since the value is selected according to the properties of the melt, the steady and continuous melting process of the melt mainly composed of incinerated ash in the thermite melting furnace can be reliably controlled.
[0014]
By the way, as in the present invention, when the material to be melted is introduced into the furnace by the charging means in accordance with the temperature in the furnace, the material to be melted is introduced into the furnace at a constant interval as in the prior art. In comparison, the level of the material to be melted in the hopper that is attached to the melting furnace and stores the material to be melted does not necessarily decrease at a constant rate. For this reason, there is no problem in supplying the material to be melted into the hopper manually by visually checking the level in the hopper. However, if the material to be melted is automatically supplied to the hopper using the conveying means. If the transport means is operated at a constant speed or intermittently at regular intervals, the level of the melted material in the hopper will greatly fluctuate. There is a risk of overflow or a shortage of the melt to be charged by the charging means.
[0015]
In this case, if a second control means for starting and stopping the conveying means for conveying the molten material according to the level of the molten material in the hopper is provided, the level of the molten material in the hopper is detected. Since the second control means can start and stop the conveying means based on the level signal, a desired amount is always in the hopper even when the operation of the making means becomes irregular. It becomes possible to store the material to be melted.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
1 to 3 show an embodiment in which the apparatus for introducing a material to be melted into a melting furnace according to the present invention is applied to a thermite melting equipment.
In the figure, reference numeral 1 denotes a thermite melting furnace in the thermite melting equipment, and reference numeral 2 denotes a hopper that is integrally provided with the melting furnace 1 and stores a material to be melted that is an object to be melted. An opening 3 communicating with the melting furnace 1 is formed at the bottom of the hopper 2, and a material to be melted in the hopper 2 is put into the melting furnace 1 at a position facing the opening 3. A pusher (feeding means) 4 is provided. Reference numeral 5 denotes a cylinder that reciprocally drives the pusher 4 with hydraulic oil supplied from the hydraulic motor 6.
[0017]
On the other hand, on the upper part of the hopper 2, a means for conveying a material to be melted is provided.
The conveying means includes a supply hopper 7 for storing incinerated ash (melted material) to be melted, a conveyor 8 for conveying the incinerated ash discharged from the supply hopper 7, and an incineration conveyed by the conveyor 8. Schematic configuration of a supply device 9 for supplying a thermite melting agent at a predetermined ratio to the ash, and a screw conveyor 10 for weighing the incinerated ash mixed with a certain ratio of thermite melting agent sent from the conveyor 8 The discharge side of the screw conveyor 10 is introduced into the upper part of the hopper 2.
[0018]
Here, the thermite agent supply device 9 includes an aluminum container 11 in which aluminum dross powder as an aluminum component is stored, an iron oxide container 12 in which waste iron oxide powder as an iron oxide component is stored, and these containers 11, The aluminum dross powder and waste iron oxide powder supplied from 12 are packed in a plastic bag at a ratio of 2: 1 corresponding to the above-described reaction formula and sealed to form a thermite melting agent. And a bag supply device 13 that is supplied to the top, and is controlled to supply the thermite melting agent at a constant rate to the incinerated ash based on the weight detection signal of the screw conveyor 10. ing.
[0019]
On the other hand, a non-contact level detector 14 using ultrasonic waves or the like for detecting the level of the material to be melted supplied by the conveying means is attached to the side wall of the hopper 2. Based on the detection signal from the level detector 14, the conveyor 8, the thermite supply device 9 and the screw conveyor 10 are simultaneously started and controlled to be stopped simultaneously by a second control means (not shown). It has become.
[0020]
Further, the melting furnace 1 is formed with an inclined surface 1a at the bottom where the material to be melted is continuously supplied to the opening 3, and a melt discharge portion 1b is formed below the inclined surface 1a. ing. Furthermore, a plurality of (four in the figure) burners (heating means) 16 are disposed on the ceiling portion 15 inclined corresponding to the inclined surface 1a, and at the central portion surrounded by the burners 16. A thermocouple type temperature detector 17 is provided. Incidentally, the temperature detector 17 is attached at a position for detecting the atmospheric temperature in the melting region of the melted material that moves the inclined surface 1a downward. Control means 18 (first control means) for reciprocally driving the pusher 4 through the cylinder 5 by starting and stopping the hydraulic motor 6 based on a detection signal from the temperature detector 17 is provided. The control set value in the control means 18 is a value selected in the range of 1200 ° C. to 1400 ° C., preferably in the range of 1250 ° C. to 1350 ° C., depending on the type of furnace, the properties of the material to be melted, and the like.
[0021]
A slag discharge conveyor 20 storing water at the bottom is disposed below the discharge part 1 b of the melting furnace 1, and the slag transferred by the conveyor 20 is stored in the slag bunker 21.
On the other hand, the exhaust gas discharged from the melting furnace 1 is recombusted in the secondary combustion chamber 22, and after dioxins are decomposed, at least 550 ° C. or less by direct cooling using the latent heat of water in the exhaust gas cooling device 23. , Preferably rapidly cooled to 450 ° C. or less, and then recovered in the heat recovery means 24 such as a waste heat boiler, an air preheater used for combustion of the burner 16, an air heater for white smoke prevention, and the like It is detoxified separately by a filter dust collector such as a filter and discharged from the chimney.
[0022]
Next, an embodiment of a method for charging a material to be melted into the melting furnace according to the present invention will be described using the apparatus for charging a material to be melted into the thermite melting furnace having the above configuration.
First, while transferring the incinerated ash (melted material) in the supply hopper 7 by the conveyor 8, based on the load of the screw conveyor 10, a thermite agent is supplied from the supply device 9 for every fixed ratio of the incinerated ash, and the thermite The incinerated ash mixed with the agent is supplied from the screw conveyor 10 into the hopper 2. On the other hand, in the melting furnace 1, the furnace temperature is raised by the burner 16, and the furnace temperature is continuously detected by the temperature detector 17. As shown in FIG. 3, when the furnace temperature reaches a set value selected from a range of 1200 ° C. to 1400 ° C., preferably a range of 1250 ° C. to 1350 ° C., the control means 18 (first control The hydraulic motor 6 is driven by means), and the pusher 4 is reciprocated by the cylinder 5, whereby the material to be melted at the bottom of the hopper 2 is put into the inclined surface 1 a of the melting furnace 1 from the opening 3.
[0023]
Then, the temperature in the furnace once decreases due to the introduction of a new melt, but when the furnace temperature rises to about 1100 ° C. due to heating by the burner 16, the thermite agent causes a thermite reaction, The incineration ash is melted by the heating by the burner 16 and the amount of heat generated by the thermite reaction. Then, the molten incineration ash flows down along the inclined surface 1 a and is discharged from the discharge portion 1 b at the bottom to the slag discharge conveyor 20.
In this way, when the temperature in the melting furnace 1 rises and the furnace temperature reaches the set value, the pusher 4 is reciprocated again by the temperature detector 17 and the control means 18, and a new melted material is melted. It puts in in the furnace 1, and the above process is repeated sequentially.
[0024]
In parallel with this, when the level of the melted material in the hopper 2 reaches a predetermined level, a signal from the level detector 14 that has detected this level indicates that the conveyor 8 and the thermite agent The operations of the supply device 9 and the screw conveyor 10 are stopped simultaneously. When the level of the melted material falls below a predetermined value due to the insertion by the pusher 4, the operation of the conveyor 8, the supply device 9 and the screw conveyor 10 is restarted simultaneously by the detection signal from the level detector 14. The
[0025]
As described above, according to the apparatus for supplying a material to be melted into the melting furnace and the supplying method using the same, the temperature in the melting furnace 1 is always detected by the temperature detector 17, and the detected furnace temperature is When the set value selected from the range of 1200 ° C. to 1400 ° C., preferably from the range of 1250 ° C. to 1350 ° C. is reached, the pusher 4 is driven by the control means 18 and the material to be melted is put into the melting furnace 1. Since it is charged, the inside of the melting furnace 1 can always be maintained in an optimum atmosphere for the melting process, so that the melting process of the material to be melted can be carried out smoothly and continuously.
[0026]
At this time, the position where the temperature in the furnace is detected by the temperature detector 17 is set as the melting region of the material to be melted, and the set temperature is in the range of 1200 ° C to 1400 ° C, preferably in the range of 1250 ° C to 1350 ° C. Since the selected value is used, it is possible to reliably control the steady and continuous melting treatment of the incinerated ash by reliably generating the thermite reaction in the thermite melting furnace 1.
[0027]
In addition, in parallel with the above-described introduction of the melt, the level detector 14 detects the level of the melt in the hopper 2 and the second control means controls the transport means based on the level signal. Since starting and stopping can be performed, a desired amount of melted material can be always stored in the hopper 2 even when the melted material is not equally spaced by the pusher 4.
[0028]
In the above embodiment, the charging method for charging the melt containing the thermite melting agent for causing the thermite reaction to the incinerated ash in a predetermined ratio in the thermite melting furnace 1 according to the present invention. However, the present invention is not limited to this. However, the present invention is not limited to this, and other melting furnaces, etc. for melting the same material to be melted mainly composed of incineration ash in an oxygen-enriched atmosphere. The present invention can be similarly applied to a melting furnace of this type.
[0029]
As described above, according to the present invention described in claim 1, since the material to be melted into the melting furnace by the charging means is input based on the furnace temperature, the inside of the melting furnace is It is possible to always maintain the atmosphere optimal for the melting treatment, and as a result, it is possible to continuously and smoothly carry out the melting treatment of the melted material mainly composed of incinerated ash. Therefore, after the furnace temperature is reliably raised to a temperature at which the thermite reaction occurs or higher and a desired melting process is performed, a new material to be melted can be charged.
[0030]
Further, when the conveying means for conveying a melt to the hopper is provided, detects the level of the melt in the hopper, the second control means, the conveying based on the level signal Since the means can be started and stopped, a desired amount of the melt can be stored in the hopper at all times even when the melt is charged by the charging means at an equal time interval. The effect is obtained.
[Brief description of the drawings]
FIG. 1 is an overall schematic configuration diagram showing an embodiment of the present invention.
FIG. 2 is a plan view of a melting furnace showing the arrangement of temperature detecting means in the embodiment.
FIG. 3 is a control flowchart in the embodiment.
[Explanation of symbols]
1 Melting furnace 2 Hopper 3 Opening 4 Pusher (loading means)
8 Conveyor 9 Thermite supply device 10 Screw conveyor 14 Level detector 16 Burner 17 Temperature detector 18 Control means (first control means)

Claims (1)

In a method in which a material to be melted mainly containing incinerated ash and containing a predetermined amount of thermite melting agent for causing a thermite reaction with respect to the incinerated ash is charged into a thermite melting furnace having a heating means by a charging means. The temperature in the melting region of the material to be melted is detected as the furnace temperature, and when the temperature reaches a set value selected from the range of 1200 ° C to 1400 ° C , the charging means is driven. A method of charging the melt into the melting furnace, wherein the melt is charged into the melting furnace.

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